1 // Copyright 2020 The Pigweed Authors 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); you may not 4 // use this file except in compliance with the License. You may obtain a copy of 5 // the License at 6 // 7 // https://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 11 // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the 12 // License for the specific language governing permissions and limitations under 13 // the License. 14 #pragma once 15 16 #include <array> 17 #include <cstddef> 18 #include <span> 19 20 #include "pw_bytes/span.h" 21 #include "pw_result/result.h" 22 #include "pw_stream/stream.h" 23 24 namespace pw::stream { 25 26 class MemoryWriter : public Writer { 27 public: MemoryWriter(ByteSpan dest)28 MemoryWriter(ByteSpan dest) : dest_(dest) {} 29 bytes_written()30 size_t bytes_written() const { return bytes_written_; } 31 ConservativeWriteLimit()32 size_t ConservativeWriteLimit() const override { 33 return dest_.size_bytes() - bytes_written_; 34 } 35 WrittenData()36 ConstByteSpan WrittenData() const { return dest_.first(bytes_written_); } 37 data()38 const std::byte* data() const { return dest_.data(); } 39 40 private: 41 // Implementation for writing data to this stream. 42 // 43 // If the in-memory buffer is exhausted in the middle of a write, this will 44 // perform a partial write and Status::ResourceExhausted() will be returned. 45 Status DoWrite(ConstByteSpan data) override; 46 47 ByteSpan dest_; 48 size_t bytes_written_ = 0; 49 }; 50 51 template <size_t kSizeBytes> 52 class MemoryWriterBuffer final : public MemoryWriter { 53 public: MemoryWriterBuffer()54 MemoryWriterBuffer() : MemoryWriter(buffer_) {} 55 56 private: 57 std::array<std::byte, kSizeBytes> buffer_; 58 }; 59 60 class MemoryReader final : public Reader { 61 public: MemoryReader(ConstByteSpan source)62 MemoryReader(ConstByteSpan source) : source_(source), bytes_read_(0) {} 63 ConservativeReadLimit()64 size_t ConservativeReadLimit() const override { 65 return source_.size_bytes() - bytes_read_; 66 } 67 bytes_read()68 size_t bytes_read() const { return bytes_read_; } 69 data()70 const std::byte* data() const { return source_.data(); } 71 72 private: 73 // Implementation for reading data from this stream. 74 // 75 // If the in-memory buffer does not have enough remaining bytes for what was 76 // requested, this will perform a partial read and OK will still be returned. 77 StatusWithSize DoRead(ByteSpan dest) override; 78 79 ConstByteSpan source_; 80 size_t bytes_read_; 81 }; 82 83 } // namespace pw::stream 84